Production method capable of reducing dendritic segregation of hot rolled coiled plate Q345B

A technology of Q345B and dendrite segregation, applied in the production field of reducing Q345B dendrite segregation of hot-rolled coils, can solve problems such as toughness reduction, heat treatment solid solution strengthening failure, etc.

Active Publication Date: 2018-04-06
天铁热轧板有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention aims to overcome the defects of the prior art and provide a production method for reducing dendrite segregation of hot-rolled coil Q345B. The reduction of toughness and the failure of heat treatment solid solution strengthening caused by Ti

Method used

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  • Production method capable of reducing dendritic segregation of hot rolled coiled plate Q345B
  • Production method capable of reducing dendritic segregation of hot rolled coiled plate Q345B
  • Production method capable of reducing dendritic segregation of hot rolled coiled plate Q345B

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Experimental program
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Effect test

Embodiment 1

[0024] Embodiment 1: The chemical composition weight percent of the hot-rolled coil Q345B of the present invention is as follows: C: 0.12%, Mn: 0.59%, Si: 0.12%, P: 0.020%, S: 0.010%, Al s : 0.010%, Cr: 0.7%, the rest is iron and unavoidable impurities.

[0025] Mechanical properties: yield strength 431MPa, tensile strength 545MPa, impact energy 187J, elongation (%) 27.5.

[0026] Metallographic analysis: grain grade / grade 11.5, banded structure / grade 0.5.

[0027] Effect evaluation: the structure is uniform and fine, the strength and toughness are high, the level of type A inclusions is low, the size is 60 μm, and the level of band structure is reduced.

Embodiment 2

[0028] Embodiment 2: The chemical composition weight percent of the hot-rolled coil Q345B of the present invention is as follows: C: 0.06%, Mn: 0.4%, Si: 0.15%, P: 0.021%, S: 0.011%, Al s : 0.005%, Cr: 1.0%, and the rest are iron and unavoidable impurities.

[0029] Mechanical properties: yield strength 416MPa, tensile strength 527MPa, impact energy 197J, elongation (%) 28.

[0030] Metallographic analysis: grain grade / grade 11, band structure / grade 0.5.

[0031] Effect evaluation: the structure is uniform and fine, the strength and toughness are high, the level of type A inclusions is low, the size is 60 μm, and the level of band structure is reduced.

Embodiment 3

[0032] Example 3: The chemical composition weight percent of the hot-rolled coil Q345B of the present invention is as follows: C: 0.08%, Mn: 0.487%, Si: 0.111%, P: 0.019%, S: 0.012%, Al s : 0.005%, Cr: 0.862%, N: 0.010%, and the rest are iron and unavoidable impurities.

[0033] Mechanical properties: yield strength 445MPa, tensile strength 564MPa, impact energy 206J, elongation (%) 27.4.

[0034] Metallographic analysis: grain grade / grade 11.5, banded structure / grade 0.5.

[0035] Effect evaluation: the structure is uniform and fine, the strength and toughness are high, the level of type A inclusions is low, the size is 60 μm, and the level of band structure is reduced.

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Abstract

The invention discloses a production method capable of reducing dendritic segregation of a hot rolled coiled plate Q345B. The production method is characterized in that the hot rolled coiled plate Q345B comprises the following chemical components of, by weight, 0.06-0.12% of C, 0.4-0.59% of Mn, 0.06-0.15% of Si, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.005-0.030% ofAls, 0.6-1.0% of Cr and the balance iron and unavoidable impurities. With respect to the matching ratios of the components, the contents of Mn and C are reduced, Cr is added and is used to exert solution strengthening and grain refining functions in steel, and a part of Mn and C is replaced, so that dendritic crystals and center segregation behaviors of manganese and carbon are weakened obviouslyunder the condition that the mechanical properties of strip steel are not affected, ferrite grains are refined, the spacing between pearlite pieces is reduced, the toughness and cold-working propertyof the steel are improved, the banded structure level of the rolled strip steel is lowered, the structure is refined, and the strength and mechanical property which meet the requirements are obtained.

Description

technical field [0001] The invention relates to a production method of hot-rolled coils, in particular to a production method for reducing Q345B dendrite segregation of hot-rolled coils. Background technique [0002] Q345B is a low-carbon alloy steel with good comprehensive mechanical properties, low temperature performance, cold stamping performance, welding performance and machinability. It is widely used in bridges, vehicles, ships, buildings, pressure vessels and other fields. At present, the production of hot-rolled coil Q345B by major steel mills mostly adopts the silicon-manganese deoxidation alloying process. Manganese exists in the steel as an important deoxidizing element. The Mn content in the steel is generally controlled within the range of 1.1-1.5%, and the C content is controlled within 0.15 -0.20% range. The problem of this traditional production process is that the steel contains high manganese and carbon content, and segregation is easy to form between den...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/18C22C38/06C22C38/04C22C38/02C22C33/06C21D8/02
CPCC21D8/0226C22C33/06C22C38/02C22C38/04C22C38/06C22C38/18
Inventor 黄伟丽杨志刚韩伟旗
Owner 天铁热轧板有限公司
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